Electrical measuring instrument.



No. 819,706. PATENTED MAY 8, 1906 T. ABTMBYER. ELBGTRIGAL MEASURING INSTRUMENT.

APPLICATION FILED SEPT. 10. 1904.

3 SHEETS-SHEB lv WITNESSES: INVENTOR ATTO'RNEY- No. 819,706 EATENTED MAY 8, 1906 T. ABTMEYER. ELECTRICAL MEASURING INSTRUMENT.

APPLICATION FILED SEPT-10, 1904.

3 SHEETSSHEET 2.

' i'umunmmi I *illlllllllllll' w v H mm 1 WAT WITNESSES: A INVENTOR I r i ATTORNEY PATENTED MAY 8, 1906.

T. ABTMEYER.

ELECTRICAL MEASURING INSTRUMENT.

APPLICATION FILED SEPT. 10, 1904.

3 SHEETS-SHEET 3.

- WITNESSES:

ran 'srarns;

PATENT orr'ron.

THEODORE ABTMEYER, OF VVILKINSBURG, PENNSYLVANIA, ASSIGNOR' TO WVESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPO- :RATION or PENNSYLVANIA.

ELECTRICAL MEASURING INSTRUMENT.

Specification of Letters Patent.

Patented May 8, 1906.

Application filed September 10, 1904., Serial No. 223.986.

new and useful Improvement in Electrical Measuring Instruments, of which the following is a specification.

My invention relates to instruments for measuring electricity, and particularly to the indicating devices which constitute parts of such instruments.

The object ofmy invention'is to provide means whereby the forces that act to produce deflections of the movable member of a measuring instrument may be indicated at a suitable locationand be read without difliculty.

Another object of my invention is to provide such indicating means as will permit of the use of horizontal-axis instruments in lieu of many of the vertical-axis instruments that have been heretofore generally used.

Electrodynamometers and instruments of similar construction are unsuitable for many purposes, owing to the fact that deflections of the movable member are indicatedupon a dial by a pointer in such manner that they may be read only with difficulty and inconvenience. Such instruments are also unsuitable for portable use, since mercury-cups or delicate suspension means, or both, are necessary features. By means of my invention all such objectionable details are avoided, and hence the instrument is peculiarly adapted to portable use as a precision or calibration instrument.

My invention is illustrated in the accompanying drawings, in which Figure 1 is a plan view with the cover removed of the instrument constructed in accordance therewitl1. Fig. 2 is a view in side elevation of the instrument shown in Fig. 1, one side of the case having been removed and the cover being shown in section. Fig. 3 is a detail view of one of the pedestals for supporting the movable coil of the instrument. Fig. 4 is a sectional view on the line IV IV of Fig. 2;-and Fig. 5 is a part sectional viewon the line V V of Fig. 1.

Rigidly mounted upon a suitable base lby.

means of an insulating-strip 2 and bolts 3,

which pass through the said strip and base,

is a coil 4, the plane of the coi." being vertical.

Supported in the field of the coil 4 with? its plane horizontal and its major axis substantially coincident with that of: the coil 4 is a coil 5. vThe supports for this coil comprise knife-edge trunmons 6 an'd7, secured to the coil in any suitable manner in line with its major axis and pedestals Sand 9, having bearing-surfaces. 10 near the free ends thereof upon which the knife-edges of the trunnionsfi and 7 rest. The pedestal 9 is provided-with a stop 11, against which the pointed end 12 of the trunnion 7 bears, longitudinal move; ment of the coil 5 being thereby prevented."

Oppositely coiled sprlngs 13, and, 14 are mounted with their inner ends connected, re: spectively, to the knife-edge trunnions 6 and- 7 and with their outer ends connected to the pedestals 8 and 9 by means of screws or pins 15, having their ends solid. These springs are provided merely for the purposeof con ducting the current into and out of the movable coil 5.

Secured to one end of the coil 5 is a suitable I pointer 16, the purposeof which will be hereinafter more fully set forth. Means for raise ing the movable coil 5 from its bearings when the instrument is not in use comprise springs 1 7, which are adapted to sustain the Weight of the coil 'posts 18, to thefree ends of which the springs "17 are secured and which are joined at their other ends by means ofbars 19, projections 20, secured to said bars, eccentrically-mounted cams 21, which are adapted to engage the projections 20,'and suitable operating-handles 22.

When the handles 22 are in the fullline position shown in Fig. 2, the coil 5 is supported by means of the knife-edge bearings and the instrument-is in condition for use. 1 In this case the springs 17 serve-to prevent an undue amount of rotation of'the' coil 5, and as cushions to prevent injurious shocks'in case the coil is turned quickly to thelimit of its movement.

When the instrument is not inuse, the operating-handles 22 may be thrown to the dotted-line position, in which case the posts'18 and the attached springs 17- are raised, so as to support the coil 5 independently of its knife-edge bearings.

The free end of the knife-edge trunnion 6 is provided with a bushing 23, towhich the Mounted uponthe knob 29 is a metallicbushing 30, having a cylindrical ortion 31 and an annular portion 32. Rigi y secured to the c lindrical portion 31 of the bushing is a was er 33, and between the washer 33 and the annular portion 32 of the bushing is loosely mounted a worm-wheel 34. Interposed between the worm-wheel 34 and the washer 33 is a spring-washer 35, that presses the worm-wheel 34 against a felt or other fibrous washer 36, which is interposed between theworm-wheel and the annular portion 32 of the bushing 30. Exact or line adjustment is effected by means of wormwheel 34 and worm 37, the latter being formed or mounted upon a spindle 37 having a knob. or head 37".

Mounted upon the inner. end of the arbor 28 is a cylindrical scale 38, and adjacent thereto at the upper side is a stationary index and Vernier-scale 39. When the instrument is in its zero position, the pointer 16 is adjusted so that it lies directly over the stationary index 39 and the zero-point on the rotary cylindrical scale 38. Directlyabove the end of the pointer and the two scales is a window 40 in the cover of the case 41 of the instrument.

In the operation of the instrument currents are passed through the coils 4 and 5, and the reaction'between-the two coils causes the coil 5 and its pointer 16 to turn upon the knife-ed e trunnions 6 and 7 against the ac of t e stationary Vernier-scale.

, tion of the instrument.

tion of t e springs 24 and 25. In order to ascertain the value of the force which caused the movement ofthe coil 5, thearbor 28 and the scale 38 are turned, by means of the knob 29, until the springs 24 and 25 return the ointer to approximately the zero-point Exact adjustment of the pointer may be efi cted by means of the worm 37 and the we wheel 34, since the frictional engagement between the spring-washer 35 and the adjacent parts willcause the movement of the worm-wheel to be transmitted to the arbor 28. When the magnetic force causing the rotation of the coil 5is exactly. counterbalanced by the torsion of the spiral springs 23 and 24, the pointer 16 will assume a osition coincident with the zero-point on t e stationary scale 39 and the division onthe rotatable "scale 38, which lies directly under the pointer and opposite the index, may be read as the deflec The details of construction may of course be varied from what I have specifically shown and described without departing from my invention. I

I claim as my invention-- 1. In an electrical measurin instrument, the combination with a movabIe member, of

a pointer, a spring concentric with the axis of I said movable member and having one end ,at-

tached thereto, an arbor to which the other end of the spring isattached, arotatable scale- .carried by said arbor, and astationary index adjacent to said rotatable scale. 2. In an electrical measurin instrument, a stationary coil and a movab e coil havin coincident axes, a spring concentric with-sai axes and having one end connected to the movable coil, an arbor to which the other'end of the spring is attached, arotatabl'e scalecarri ed by the arbor, and a stationary-index and Vernier-scale adjacent to said rotatable scale. 3. In an electrical measuring instrument, the combination with a movable member, of two oppositely-coiled spiral springs each of which has one end attached thereto, an arbor to which the other ends of the springs are attached, a rotatable scale carried by the arbor, and a stationary index adjacent to said rotatable scale.

4. In an electrical measuring instrument, 1

movable coil, spiral springs having their inner ends attachedthereto, an arbor to which the outer ends of the springs are attached, a pointer carried by the movable coil, 2. rotatable scale carried by the arbor, and a stationary index adjacent to said rotatable scale.

5. In an electrical measuring instrument, a stationary coil and a movable coil having coincident horizontal axes, pivots attached to said movable coil, spiral springs each having one end attached to one of said pivots, an arbor to which the other ends of the said springs are attached, a pointer carried by the movable coil, a rotatable scale carried by the arbor, and a stationary index and Vernier-scale adjacent to said rotatable scale.

6-. In an electrical measuring instrument,

the combination with a stationa y coil, and a movable coil having a pointer, 05 a stationary scale and a movable scale adjacent to each other and to the pointer, and a yielding, re-- yieldin resilient connection between the movab e scale and the movable coil.

8. In an electrical measuring instrument, the combination with a stationary coil and a movable coil in inductive relation to each other, said movable'qoil having apointer, of a stationary index, and a movable scale adjacent'to-said pointer and one or more sprin s conlnecting, he movable coil and the movabIe sca e.

9. Inan electrical measuring instrument, the combination with a stationary coil and a coil supported I upon knife-edge bearin s in inductiye relation-to said stationary coi and provided with'a pointer, of a stationary index, a movable scale and oneor more springs connecting said movablescale to said movable coil. I f

10. In an electrical measuring instrument,

the combination with a stationary coil, a

movable coil mountedhpon knife-edge bearings and provided with a pointer, and means for raising and supporting said coil independentlyrof its bearings, of a stationary index', a

posed between saicl scale and the movable coil.

11-.* In an electrical'measuring instrument; the combination with a stationary coil and a movable coil pivotally supported in inductive relation thereto and having a pointer, of a stationary index, a rotatable scale, one or more -s rings connecting said scale to said movab ecoil, and means for rotat-i-ngfsaid scale.

In testimony whereof I have hereunto subscribed my name this llth day of August, 1904.

THEODORE ABTMEYER. Witnesses:

FRANK BRADLEY, BIRNEY I-I1NEs 

